Reserve primary battery



Calif., assignors to Hughes Aircraft Company, Culver City, Calif., a corporation of Delaware Application May 1, 1956, Serial No. 582,623

Z Claims. (Cl. 136-90) The present invention relates to primary batteries, and more particularly to a reserve primary battery which may be remotely activated.

Conventional primary or electrolytic cells are subject to a self-discharging action during storage, and it is therefore highly desirable that the batteries be maintained in an inactive condition until immediately prior to placing the battery in service. Heretofore, it has been proposed that the electrolyte for the cells be maintained in a separate chamber from the cells, the electrolyte chamber preferably being housed within the battery case but normally isolated from the cells of the battery until such time as it is desired to activate the battery. While it is possible to utilize a separate chamber or reservoir for the electrolyte for each of the cells of the battery, it is obvious that a considerable simplification in the structure of the battery and the equipment necessary to accomplish its activation may be achieved if a single chamber can be utilized as the reservoir for the electrolyte to be injected into a plurality of cells.

Unfortunately, such a construction presents a number of problems which have heretofore only been partially solved. Since the electrolyte itself is a conductor f electricity, particular care must be taken to prevent the formation of short circuit paths between the cells through the common electrolyte reservoir. It is also necessary to ensure an equal distribution of electrolyte from the reservoir into each of the cells of the battery. The common reservoir batteries previously proposed generally rely on gravity or centrifugal force to achieve equal distribution of electrolyte from the common reservoir. Such batteries, while reliable for operation under the conditions for which they were designed, quite obviously cannot be used under conditions where it is impossible to predict or control the position in which the battery will be operated.

It is, therefore, an object of the present invention to provide an improved reserve primary battery in which the electrolyte for a plurality of cells is stored in a single chamber or reservoir prior to activation.

A further object of the present invention is to provide an electrolytic battery of the class described which is not dependent on either position or motion to assure its proper operation.

A further object of the present invention is to provide a battery of the class described which utilizes a common reservoir for the electrolyte to be injected into a plurality of cells and includes means for preventing excessive discharge of the cells through any electrolyte remaining within the common electrolyte reservoir.

Yet another object of the present invention is to provide a remotely activated reserve primary battery which is simple in construction and positive in operation, utilizing a common electrolyte reservoir for a plurality of cells, and being arranged to provide for an equal distribution of electrolyte among the cells of the battery.

A reserve primary or electrolytic battery, according to the present invention, comprises a plurality of battery cells, each containing a set of battery plates, an electrolyte reservoir, an electrolyte manifold` interconnecting the iisgrti Pathted Sept. 22,` 1959 reservoir and each of the cells of the battery, and means for forcing electrolyte from the reservoir into each of the cells. The portions of the electrolyte manifold inter-A connecting each of the cells, while of suicient dimen sion to permit the ready ow of electrolyte therethrough, are sufficiently long and small in cross-sectional area to insure a leakage path through the electrolyte in the manifold between cells which is of insufficient conductivity to seriously detract from the performance of the batteryL In addition, the reservoir, cells, and manifold are sealed against atmospheric pressure in order to ensure the equal distribution of electrolyte among the cells of Ithe battery upon activation.

The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description considered in connection with the ac* companying drawing in which an embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawing is for the purpose of illustration and description only, and is not intended as a definition of the limits of the invention.

Fig. 1 is a perspective view of a battery provided with electrolyte charging means constructed in accordance with the present invention; and

Fig. 2 is a side elevational view in cross section of the battery of the present invention.

Referring now to Figs. 1 and 2, wherein like reference characters refer to the same elements inthe several views, a reserve primary battery according to the present invention comprises a container or case 10, having a cell portion generally delined by the numeral 11 and an electrolyte reservoir portion 12. Cell portion 11 comprises a plurality of cell sections for receiving positive and negative battery plates, each cell section forming a battery cell. For convenience of illustration, the battery plates are symbolically shown in Fig. 2, being disposed within each cell in a conventional manner. An electrolyte manifold 13 is arranged to interconnect electrolyte reservoir 12 and each of the cells of the battery for conducting electrolyte from the reservoir to the cells upon activation of the battery in a manner to be described.

More particularly, as depicted most clearly in Fig. 2,

cell portion 11 of the battery is positioned to occupy the upper portion of battery case 10, while electrolyte reservoir 12 is positioned to occupy the bottom or lower portion of battery case 10. Manifold 13 is connected to reservoir 1:2 at one side of the battery case, preferably the end of the reservoir and is arranged to form a conductive passage for electrolyte from the reservoir into anotherside of the top of each ofthe cells in cell portion 11. The; manifold, accordingly, comprises two sections, a verticali, transmission section 23, and a discharging section 241i` arranged to pass across the top of each ofthe cells, the: manifold discharging section being adapted to discharge: electrolyte into each cell through a plurality of electrolyte nozzles 21.

As will be explained more fully hereinafter, the arrangement of the manifold in the manner depicted contributes to the utility of the present invention for operation with the battery in any position without danger of electrolyte being returned to the reservoir through the actionv of gravity or failure of the activating mechanism.

Electrolyte reservoir 12 contains, in addition to the electrolyte for the battery, a thin, exible bladder 14 which is arranged to be inflated by means of pressure applied to the bladder from an external source through an inlet 15. As will be readily understood, inflation of bladder 14 will displace electrolyte from reservoir 12, causing the electrolyte to flow from the reservoir into the manifold and into the cellseof the battery? Inordetjy to prevent electrolyte fromilowing from the reservoir prior to activation, as during normal handling and movement, a thin frangible diaphragm 16 covers the port 17 between the reservoir and manifold.` A puncture Iiedle,

1S is provided opposite frang'ible diaphragm 16 topunc; ture the diaphragm when the diaphragm deflects under pressure of the electrolyte following activation of the battery. In addition, a ported cap 19 is provided to cover port 17, the cap functioning to prevent thel ulstenoeu bladder from impinging. against needle 1,8 and being ruptured-thereby. v

Electrolyte manifold 13, asshown in Fig. 2, is arranged for passing electrolyte from electrolyte reservoir 12.upon activation of the battery to each of the, cells ofthe bat: tery, and accordingly is. provided with a plurality of elec* trolyte nozzles 21, including one nozzle for each cell of the battery, for passingelectrol'yte from the manifold into each cell. Ordinarily, the amount of electrolyte in the reservoir will be proportioned to correspond to the total; quantity required to activate all. of the cells of the battery. It will readily be understood that if the reservoirv contains an excess of. electrolyte over that absorbedlby, each of the cells so that a quantity remains in themani: fold following activation, short circuit paths through the electrolyte may be formed. Similarly, inversionof the battery may cause the electrolyte in the cells to flow back into the manifold, again forming short circuit paths. In

order to reduce the current drain4 through short circuit paths to a minimum value which will not seriously d e-V tract from the operation and normal use ofthe battery,

each of nozzles 21 and the electrolyte path in manifold, 20 should be dimensioned. to provide as small a cross sectional area and as long aV path` between cells is.

feasible.

On the other hand, electrolyte manifold 13l andthe. nozzles must be dimensione/ d toprovidethat electrolyte` be equally divided among the. cells. regardless of. theirv number. Since the nozzles are at varying distances from', the electrolyte reservoir and are fed by a common mani-V fold, an equal distribution of the electrolyte could ordi narily only be achieved bytapering themanifold or the nozzles or both to provide equal pressure, at each nozzle,v

despite the fact that the nozzles are not equi-distant from the source of pressure.

Such a variation in size of manifold and nozzle, while useful in achieving an equal distribution of electrolyte'` among the cells of the battery, would seriously interferewith the previously` stated requirement that all,nozzles,

and the manifold have as small a cross-section as possible and as long a path between nozzles as is feasible. While the nozzles closest to the electrolyte reservoir could be.

dimensioned to have such a minimum cross-section, the.l nozzles more remotely located from the reservoir would.`

be of a dimension far in'excessy of this minimum value. At the` same time the. requirement that the battery be activated Within a short period of timeafter theapplication of pressure to bladder 14 .deterrnines a minimum nozzle diameter requiredto achieve the desired rate of fluid ilow. Thepresent invention satisfies thel above requirements have a-uniform cross-section throughout its discharging section 24 and each of the ,nozzles ,21,may be dimensioned. to have an identical cross-section, atA the Sametimel achieve ing an equal distribution of electrolyte-to each of the... cellsof the batteryv uponactivation.v Thus, as shown inv Figf2, common electrolyte` manifold 13 is arranged to..

pass from Vvthe, reservoirV and oyeneach of;the. cells of theA battery". Manifold 13 hasra uniform-, cross-sectional area` throughoutits discharging section 24,; and an Vequal or greater cross-sectional area, throughout rits. :transmissioncells of the battery by an electrolyte nozzle 2.1, each elec-V trolyte nozzlehaving an equal cross-sectional area less than the cross-sectional area of the manifold. If the battery is sealed in the manner described, activation of the battery will produce an equal distribution of electrolyte among its various cells.

Considering now the activation of the vbattery thus described, high pressure gas applied to inlet 15 from pressure tank 25T following the opening, of pressure release valve-26 will expand in bladde 14. This pressurewill' be transmitted through the electrolyte to deflect the frangible diaphragm, 16 AsA soon as the pressure 'has risen to a point at which the diaphragmhas deected against puncture needle 13, the needle will' pierce the diaphragm and the electrolyte under pressure will flow through the opening andinto manifold 23 and fromvthence into. each ofthe cells of'thelba'ttery. Ordinarily, the amount of' electrolyte in'reservoir 12 will be proportionedto provide suflicientA electrolyte for each of the cells which` will, asT soon as the battery is activated, be distributed equally amongl the various cells of the-battery. While the electrolyte reservoir is disposed beneath the battery, the, electrolyteis forced'into each: cellfrom the top and, accordingly, maintaining the `electrolyte in the ,cells is not dependent upon` the continuous, application of" pressure to` the bladder..

At thesam'e time, thephysical inversion of the battery willcause-only asmall quantityn of electrolyte. to ow. intoy the manifold: as the liquid; in the cells and manifold" activation of the battery and passed in equal portions into,

eachof the cells of the battery upon activation.

Whatisclaimedas new is: l. In a delayed action battery havinga case, a plu rality ofcells in saidcase, electrolyte lillingopenings atY upper ends ofeach-oftsaid'rcells anda common' manifold' interconnecting said openings, the combination with' said battery of an electrolyte supply and" delivery apparatus:

comprising: a'A container for` said electrolyte,psaidjconf` rainer being disposed in association' withsaid' battery andV onuasidelthereof` remote from said openings and said manifold; a-bladder in said container; means for'in'- flating said bladder; and passage means disposed'between" said container. and said manifoldfor conducting-cleo` trolyte theretoupon inflation of said bladder, saidlpassage means disposedparallel to axes extending individually through each of-said cells and said iillingopenings thereof, saidpassage means having a volumn substarie tially. less thanthe Vvolume of any one of said cells,

whereby, upon inversion of said battery and detlationfofsaid bladder, to permit electrolyte outflow fromsaid Icells onlyto anextentwherein common levelsare established in said cells andsaid passage means.

2. A delayedA action battery` accordingY to claim l' wherein;;Said';containeris secured/toa lower surface off said battery case.

References .Cited inthe tile` of this patent UNITED STATES PATENTS 851,353 Hite Apr. 23, 19o-'l 2,529,511 Murphy Nov. 14, 1950.. 2,594,879 Davis Apr. 29, 1952,- 2,674,946 Hjelm Apr.- 13, 1954 FOREIGN yPATENTS Germanyd Nov. 15, 1956' 

